Hose handling arrangement for lift truck



Nov. 28, 1961 s. E. FARMER ETAL 3,010,594

HOSE HANDLING ARRANGEMENT FOR LIFT TRUCK Original Filed Sept. 14, 1959 01 'I u mill! 4 H.

I 35 I 1N VEN TOR5 A I i 1 7 Stanley E Farmer I L BY S/uarf R. D/die/ ;-35a 1 :5; l

I I ih 8 B are 35a Buck/70m, Chen am ATTORNEYS United States Patent 3,010,594 HOSE HANDLING ARRANGEMENT FOR LIFI TRUCK Stanley E. Farmer and Stuart R. Didtel, Portland, 0reg.,

assignors to Cascade Manufacturing Company, Portland, 0reg., a corporation of Oregon Continuation of application Ser. No. 839,814, Sept. 14, 1959. This'application Oct. 31, 1960, Ser. No. 66,311 Claims. (Cl. 214-653) This invention relates to lift structures and particularly to industrial lift trucks of the type in which the load carriage has one or more fluid motors for handling a load. conventionally the fluid motors assume the form of hydraulic piston and cylinder units. For convenience in description, the term hydraulic piston and cylinder unit will be used instead of fluid motor.

This application is a continuation of our prior application entitled Hose Handling Arrangement for Lift Truck, Serial No. 839,814, filed September 14, 1959.

In a typical truck of the type under consideration, there is a pair of hoses extending from a reel on the mast to a pair of double-acting piston and cylinder units on the carriage which operate a pair of clamp arms. Frequently, the hoses from one reel supply and discharge fluid from one cylinder, and a second reel and a second pair of hoses is provided for handling the demands of the other cylinder. However, for convenience, only one reel and its pair of hoses will be discussed immediately below.

When a load is to be picked up, a hydraulic piston and cylinder unit is supplied through one hose with fluid under pressure, the other hose conducting fluid discharged from the cylinder to a reservoir on the truck. After the load is clamped, it is desired to lift or lower the load with grip on the load maintained. This is normally accomplished by a vertical ram provided in association with the mast and operable to raise the carriage. As the carriage is moved the reel functions to reel in or reel out the hoses as demanded by the carriage movement.

Difficulties have been encountered with reeling in of such hoses because the hose containing the hydraulic fluid under pressure is expanded by the pressure and shortens to place slack in the other hose, which because of its looseness tends to foul up in the reeling operation and even run off the reel. This is especially true with trucks having high lift because the length of hose from the reel to the carriage in its high lift position is substantial. Also, the demand for trucks of suflicient capacity to handle heavier and heavier loads has necessitated increasing the hydraulic pressure supplied to the cylinders on the carriage. Increasing the pressure means greater expansion of a hose and consequent greater shortening thereof.

It is a main object of the present invention to provide a truck of the type under consideration in which there are means at the carriage for equalizing the pressure in the hoses after a load has been gripped, while maintaining the grip of the load arms on the load to permit the load to be raised or lowered as suits the desires of the operator of the truck.

Another object of the invention is to provide a simple valve arrangement at the carriage to accomplish the purpose set forth above.

Various other objects of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of a truck having a hose handling arrangement of the present invention, the full lines showing the carriage in a lowered position and the broken lines showing the carriage in an elevated conditron;

3,010,594 Patented Nov. 28, 1961 FIG. 2 is an enlarged elevational view of the hose handling arrangement;

FIG. 3 is a fragmentary horizontal section taken along line 3-3 of FIG. 2;

FIG. 4 is a fragmentary vertical section taken along line 44 of FIG. 2; and

FIG. 5 is a vertical midsectional view through the valve arrangement on the carriage.

Referring to FIGS. 1 and 2, the truck 11 has an extensible mast including stationary uprights 13 and movable uprights 15. As in conventional practice, the stationary uprights are tiltable backwardly and forwardly relative to the trucks body by means not shown. A ram 17 extends the mast, and through the medium of lift chains, not shown, raises a carriage generally entitled 19 along the inner uprights. The particular mast shown and the arrangement for elevating the carriage and extending the mast are meant only to be typical and not to be limiting on the invention.

The carriage 19 has a pair of load clamp arms 31 movable toward and away from one another under the influence of a pair of piston and cylinder unit-s best shown in FIG. 2, the cylinders of the units being number 33 and 35. In the particular truck shown, each cylinder has its own set of hoses for conducting fluid back and forth between the truck body and the cylinder. The description will be confined primarily to the hoses for the cylinder 35.

Referring to FIG. 1, the set of hoses for the cylinder 35 includes a pair of hoses 35a and 35b, one hose 33a of a similar pair of hoses for the cylinder 33 being also shown. The hoses 35a and 35b extend from a reel 37 to where they are connected to a valve 4-5 there being short hose sections 35a and 35b, as shown in FIG. 2, extending from the valve to the ends of the cylinder 35. The valve 45 will be described in detail hereinafter. The hoses for the cylinder 33 are similarly connected through a valve not shown to the ends of the cylinder 33 by short hose sections 33a and 33b as indicated in FIG. 2.

Referring particularly to FIGS. 2, 3 and 4, the hoses 35a and 35b are wound around a rotatable wheel body 47 of conventional construction, having a central dividing flange 49 to provide a separate reel section for each hose. A fixed stud shaft 51 shown in FIGS. 3 and 4 rotatably supports the reel, the shaft having a bracket 53 for securemeu-t to the upper end of one of the stationary uprights 13. The shaft has passages 55a and 55b for conducing fluid from a pair of hoses 65a and 65b to the upper ends of the hoses 35a and 35b. The just-mentioned ends of the hoses are connected to a hollow shaft 66 which rotatably fits on the shaft 51 and comprises a part of the reel body as is evident from FIG. 3. A valve 67 on the truck body controls the flow of fluid through hoses 65a and 65b and enables the operator to move the load arms away from one another, or toward one another, or to hold the load arms at desired positions. The valve in the latter condition cuts off the supply or discharge of fluid from the cylinders, and in the conventional truck maintains the applied pressure on the load.

Referring to FIG. 2, a housing 71 is secured to the reel body and covers a coil spring 73 which is attached at its opposite ends to the shaft 51 and the housing 71, and urges the reel body to rotate in a direction to wind up the hoses 35a and 35b, as is indicated by the arrows in FIG. 1 and FIG. 2. In assembling the parts, the hose length is selected so that the hoses are under approximately equal tension when under equal pressures. In the particular embodiment of the invention shown, the hoses are of equal length to accomplish the desired result.

When a load is to be picked up, the operator manipulates the valve 67 to move the load arms 31 inwardly to grip the load. During such operation, it may be assumed that the hydraulic fluid under pressure will be conducted through the hose 35a to the cylinder 35 and that the hose 3512 will conduct the discharge fluid from the cylinder 35 at a low pressure. The pressure in the hose 35a expands the hose to shorten its length; It is assumed that the hoses 35a and 35b are of conventional construction and thus are manufactured mainly of rubber or other elastomer material which is sufllciently flexible to enable the hose to be readily wound and unwound from the reel, and which, incidentally, permits the hoses to expand under pressure.

'As the hose 35a shortens, it pulls the reel body 47 around vagainst the resistance of the spring 73 to place slack in the hose 355.

After the load is gripped, the valve 67 is moved to its neutral position. ,In' such position, the valve 67 will cut off the supply or discharge, of fluid from'the hoses 35a and 35b and normally maintains the pressure in the hose 35a, and thus maintain the applied pressure on the load. Incidentally, this action would maintain the slack in the hose 35b were it not for the valve 45.

It can be seen, that in the normal reeling operation,

7 the slack hose 35a would tend to foul up in the reeling operation and perhaps even run off the reel body. This is obviously objectionable. The valve 45 which eliminates this objectionable operation will now be explained in connection with FIG.

A pair of elbows 75a and 7512 are connected to the ends of the hoses 35a and 35b and thread into the opposite ends of a plug 77 which tits in a suitable bore formed in the body of the valve 45 and may turn therein for a purpose to presently appear. For convenience, the body of the valve will be referred to by the reference numeral 45. The plug is retained in place by snap rings 79', and .O-ring seals 81. or equivalent .seals prevent undesirable leakage. The plug has two annular grooves 83 communi- Gating with the inner ends of the elbows by way of ports 85 formed in the plug. .The valve body 45. is formed with passages 87 placing the annular grooves 83 in communication with the opposite end portions of abore 89 closed at its ends by plugs 91. A shifta-ble valve mem her-93 fits in the bore for endwise movement and has tapered end portions 95 and 97 for engagement with check valve balls 99 and 101. The balls are pressed by spring 103 against seats 105 formed at the ends of suitable bores formed in the valve body. Conventional fittings 107 fit in the bores and retain the springs in place and are connected to the short hose sections 35a and 35b mentioned before.

The fit of the valve member 93 within the bore 89 is such as to allow leakage of fluid past the valve member from the left-handend of the bore to the right-hand end of the bore as the parts are shown in FIG. 5. In a typical unit constructed according to the concepts of the present invention, the clearance between the valve member 93 and the Walls of the bore 89 in a radial direction is a matter of a few one-thousandths of an inch. The reason for this clearance will be presently apparent. A through hole 109 is provided in the valve body to enable it to be mounted on the carriage.

In operation, the valve functions as follows. When fluid under pressure enters the valve through elbow 75a,

- der 35 is urged by the movement of the piston in the cylinder to pass through the short hose section 3511 and through the valve body 45. The check valve ball 101 would normally prevent such movement, but the fluid under pressure in the right-hand end of the bore 89 forces the valve member 93 to the left so that the tapered end 97 depresses the ball 101 to enable the discharge fluid to pass through the valve and up through the hose 35b and from there to the reservoir on the truck. The leakage past the valve member 93 is not suflicient to materially reduce the pressures in the right-hand side of the valve, and the amount of fluid lost during gripping the load by passage around the valve member 93 and then directly back and upwardly into the hose 35b is very small. 7

When the desired pressure has been applied to the load to enable it to' be handled, the valve 67 on the truck is manipulated to cut oil the supply or discharge of fluid from the hoses 35a and 35b to tend to maintain the high pressure of the fluid in the hose 35a, and incidentally maintain the discharge fluid in the hose 35b at its low pressure. However, fluid from the right-hand end of the bore 89 leaks past the valve member 93 to the lefthand side of the bore to quickly equalize the pressure in the hoses. As the pressure in the hose 35a drop the hose contracts in a radial direction and lengthens in a longitudinal direction to resume its former length. As the length of the hose increases, the spring 73 takes this up and also takes up the slack in the hose 35b. Thus, the hoses are quickly brought to a condition of equal tension. In the particular form of the invention disclosed, this means that the length of hose between the reel and the valve 45 is the same for each of the hoses 35a and 35b.

This equalizing action occurs so rapidly that the operator need not concern himself with it, and can operate the ram valve for energizing the ram 17 just after he throws the cylinder valve 67 to its neutral position. Since the hoses are under equal tension, they may be readily reeled up without danger of improper reeling.

Referring to FIG. 1 it is evident that when the carriage 19 moves from its lower position to its upper position, the'hoses 35a and 35b first extend from the reel downwardly to the carriage and then upwardly to the carriage. The plug 77 is capable of turning in the valve body to permit this reversal of positions of the hose ends relative to the reel. a

Having described the invention in what is considered to be the preferred embodiment thereof, it is desired that it be understood that the invention is not to be limited other than by the provisions of the following claims.

We claim:

l. A lift structure including a mast and a carriage movable vertically along said mast, a fluid-operated motor on said carriage for causing pressure to be applied to a load, reel means mounted on said mast and having at least two hoses extending to said carriage and communicating with said motor, one hose becoming shorter when expanded by fluid pressure therein and conducting fluid under a pressure higher than that in the other hose when pressure is being applied to a load so that said one hose tends to shorten to place slack in the other hose, and means at the carriage for equalizing the pressure in the hoses to remove the mentioned slack after the load is subjected to the desired pressure and to maintain the pressure applied to the load. 7

2. A lift truck having a mast at its front end and a carriage movable vertically along the mast, a fluid-operated motor on said carriage for causing pressure to be applied to a load, reel means mounted on said mast and having at least two hoses extending to said carriage and communicating with said motor, said reel means being operable to reel out hose or reel in hose to maintain a desired tension on the hoses, each hose becoming shorter when expanded by fluid pressure therein, valve means on the truck body for directing fluid under pressure through one hose while discharging fluid under a lower pressure from the other hose, so that said one hose tends to shorten more than the other hose to place slack in the other hose, said valve means being operable to close ofl communication between said one hose and the source of fluid under pressure after the desired pressure has been ajplied to the load, and means at the carriage for equalizing the pressure in said hoses to remove the mentioned slack after the load is subject to the desired pressure and to maintain the pressure on the load.

3. A lift truck as described in claim 2 in which the latter-named means comprises a valve.

4. A lift truck as described in claim 3 in which the valve includes a leakage passage placing the ends of the hoses at the carriage in communication with one another.

5. A lift structure including a mast and a carriage movable vertically along said mast, a fluid operated motor on said carriage for causing pressure to be applied to a load, reel means supported at a predetermined level and having at least two hoses extending to said carriage and-communicating with said motor, one hose becoming shorter when expanded by fluid pressure therein and conducting fluid under a pressure higher than that in the other hose when pressure is being supplied to a load so that said one hose tends to shorten to place slack in the other hose, and means for automatically equalizing the pressure in the hoses to remove the mntioned slack after the load is subjected to the desired pressure, and means at the carriage for maintaining the pressure applied an the load despite equalization of the pressure in said oses.

6. A lift structure including a mast and a carriage movable vertically along said mast, a fluid-operated motor on said carriage for causing pressure to be applied to a load, reel means supported at a predetermined level and having at least two hoses extending to said carriage and communicating with said motor, one hose becoming shorter when expanded by fluid pressure therein and conducting fluid under a pressure higher than that in the other hose when pressure is being applied to a load so that said one hose tends to shorten to place slack in the other hose, and means at the carriage for equalizing the pressure in the hoses to remove the mentioned slack after the load is subjected to the desired pressure and to maintain the pressure applied to the load.

7. A lift structure including a mast and a carriage movable vertically along said mast, a fluid-operated motor on said carriage for causing pressure to be applied to a load, reel means supported at a predetermined level and having at least two hoses extending to said carriage and communicating with said motor, one hose becoming shorter when expanded by fluid pressure therein and conducting fluid under a pressure higher than that in the other hose when pressure is being applied to a load so that said one hose tends to shorten to place slack in the other hose, and means for equalizing the pressure in the hoses to remove the mentioned slack after the load is subjected to the desired pressure and to maintain the pressure applied to the load, the last-named means including a pair of check valves one for association with one hose and the other for association with the other hose, said check valve opening under pressure applied from the direction of the truck body to permit the flow of fluid from the truck body to said motor, and fluid pressure operated means responsive to the pressure of the fluid in either hose to cause the check valves of the other hose to open to facilitate flow from said motor to said truck body.

8. A lift structure as recited in claim 7 in which said fluid pressure operated means comprises a double acting plunger for engaging one check valve when moved one Way or the other check valve when moved the other way and having a neutral position.

9. A lift structure as set forth in claim 8 in which said last-named means is located at said carriage and in which said plunger provides a small passage for the flow of fluid therepast for equalizing purposes.

10. A lift truck having a mast at its front end and a carriage movable vertically along the mast, a fluidoperated motor on said carriage for causing pressure to be applied to a load, reel means supported at a predetermined level and having at least two hoses extending to said carriage and communicating with said motor, said reel means being operable to reel out hose or reel in hose to maintain a desired tension on the hoses, each hose becoming shorter when expanded by fluid pressure therein, valve means on the truck body for directing fluid under pressure through one hose while discharging fluid under a lower pressure from the other hose, so that said one hose tends to shorten more than the other hose to place slack in the other hose, said valve means being operable to close ofl communication between said one hose and the source of fluid under pressure after the desired pressure has been applied to the load, means for equalizing the pressure in the hoses to remove the mentioned slack after the load is subjected to the desired pressure, and means at the carriage for maintaining the pressure applied to the load despite equalization of pressure in said hoses.

No references cited.

UNITED S A CERTIFICATE 0 Patent No, 3,010

It is hereby ce ent requiring corree corrected below.

Column 2., l

ducting line 24 for Signed and (SEAL) Attest:

ESTON e; JOHNSON Attesting Officer Stanley E. Farther et a1,

for "condueing" or ajplied rea ines .46 and 47,

line 4 i read mentione sealed this 171,

TES 5 PATENT OFF- ICE F CURRECTION November 28 1961 eve numbered patshould read as read con (1 applied hi day of April1962 DAVID L. LADD Commissioner of Patents Notice of Adverse fieaisiim in iniarferema In Interference No. 93,310 involving Patent No. 3,0105%, S. E. Farmer :mcl S. R. Dldtel, Hose handhng arrangement for 11ft truck, final declslon adverse to the patentees was rendered Aug. 13, 1963, as to claims 5, 7, 8 and 10.

[Oyficz'al Gazette November 12, 1963.] 

